Using version 12.3.1.0. Getting the source code used to be dead simple. But something’s changed. In the images included, all options that I can see (including both under source code!) lead to places with no source code in sight. Invitation to copy to clipboard is unhelpful because I don’t even understand what the clipboard is, nor where to find it. Maybe someone can solve this for me.
I downloaded the notebook under Source Code, and I can see the Manipulate code there. The notebook attached.
Demonstration-Solids-Whose-Cross-Sections-Have-the-Same-Shape-1-0-0-definition.nb (739 KB)
Thanks - this comes under “how could I be so dumb.”